1. Field of the Invention
The present invention is related to a crankcase ventilation system for a reciprocating internal combustion engine, and more particularly to an internal combustion engine suitable for installation in a railroad locomotive.
2. Disclosure Information
Reciprocating internal combustion engines utilize one or more cylinders for the purpose of generating power at a crankshaft. Because combustion is accompanied by very high pressures, some gases inevitably escape from the engine's cylinder(s) and leak between the reciprocating pistons and the cylinder walls. These gases, commonly termed “blow-by”, must be evacuated from the engine's crankcase, because without evacuation crankcase pressure will build and cause expulsion of lubricating oil past various seals.
With some non-boosted internal combustion engines, particularly throttled engines, it is possible to draw crankcase gases into the engine's induction system by naturally occurring vacuum. With certain other engines having boosting—in other words, engines which are turbocharged or supercharged, or even unthrottled engines, the intake system does not operate at a sub-atmospheric pressure and as a result, it is difficult to entrain blow-by gases into the intake.
Railroad locomotives frequently use a system called an eductor for conveying the blow-by gases from the prime mover—most often a diesel engine—to the exhaust stream exiting the engine. Unfortunately, the environment of the exhaust system causes carbonaceous material to be built up on the eductor. Such material must be removed periodically to prevent buildup of a sufficient cake of material that a fire hazard is posed to vegetation or structures adjoining railroad tracks upon which a locomotive is operating. This risk arises when a superheated piece of carbonaceous material is discharged from the locomotive only to fall upon dried grass, other vegetation, or a structure. Problems with caked materials forming within a crankcase gas eductor may be mitigated with regular cleaning of the eductor. Such a remedy poses a problem in the context of railroad locomotives, because eductors are generally mounted near the uppermost part of locomotives at the top of the internal combustion engine, with the eductor extending into an exhaust stack.
Cleaning the eductor requires either that the plumbing attached to the eductor be removed, a difficult task in the environment of a railroad locomotive, or that the eductor be cleaned by reaching down from the top of the locomotive thereby potentially imperiling the person performing the maintenance.
It would be desirable to have an eductor which is readily serviceable, so as to promote frequent cleaning, and which provides additional flow because of vacuum amplification.